Audio mixer



FIG. 1 is a front perspective view of a audio mixer showing my new design;

FIG. 2 is a top view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a front view thereof; and,

FIG. 7 is a rear view thereof.

The broken line showing on FIGS. 1-7 is for illustrative purposes only and forms no part of the claimed design. 

I claim the ornamental design for an audio mixer, substantially as shown and described. 